Precursory changes in the radon concentration of groundwater were observed prior to the Izu-Oshima-kinkai earthquake (magnitude 7.0) 14 January 1978. The distance from the epicenter to a continuous radon-monitoring station at Nakaizu was about 25 kilometers. A sudden drop and a subsequent increase in the radon concentration recorded on 9 January 1978 were significant. The size of the spike-like change was about 15 percent. After the earthquake, a remarkable increase in the radon concentration occurred.
A practical method of continuous measurement of radon in groundwater for earthquake prediction, especially suitable for field observation, is described. The detector consists of a ZnS scintillation chamber for alpha counting and a separation chamber in which radon is emanated from groundwater to the gaseous phase. The radon concentration in the gaseous phase equilibrates with that in water according to the distribution coefficient. Alpha activities of radon and its daughters (218Po and 214Po) in the scintillation chamber are counted and recorded continuously. The counting rate of about 1000 cpm/10−10 Ci Rn/1 is obtained by the detector, which has an effective volume of 1.6 1.
While various volatile organic compounds (VOCs) are known to show neurotoxic effects, the detailed mechanisms of the action of VOCs on the autonomic nervous system are not fully understood, partially because objective and quantitative measures to indicate neural abnormalities are still under development. Nevertheless, heart rate variability (HRV) has been recently proposed as an indicative measure of the autonomic effects. In this study, we used HRV as an indicative measure of the autonomic effrects to relate their values to the
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Int. J. Environ. Res. Public Health 2010, 74128 personal concentrations of VOCs measured by a real-time VOC monitor. The measurements were conducted for 24 hours on seven healthy subjects under usual daily life conditions. The results showed HF powers were significantly decreased for six subjects when the changes of total volatile organic compound (TVOC) concentrations were large, indicating a suppression of parasympathetic nervous activity induced by the exposure to VOCs. The present study indicated these real-time monitoring was useful to characterize the trends of VOC exposures and their effects on autonomic nervous system.
Mineral carbonation, which is CO 2 fixation through a carbonation reaction using alkaline earth metals, is being investigated as a carbon capture and utilization method to reduce CO 2 atmospheric emissions. Concrete sludge is an alkali waste material from the concrete industry and contains abundant calcium components. We investigated the applicability of concrete sludge for mineral carbonation. In this study, gas containing CO 2 was bubbled through the model concrete sludge solution and the effects of the solid−liquid ratio, bubbling time, gas flow rate, and the partial pressure of CO 2 on the CO 2 fixation ratio and fixation rate were investigated. The CO 2 fixation ratio decreased with increasing CO 2 bubbling time, CO 2 flow rate, and CO 2 partial pressure. The CO 2 fixation rate increased with increasing CO 2 flow rate and CO 2 partial pressure. The formation of calcite, a form of calcium carbonate, was confirmed.
In this paper we report on the asymmetric 1,3-dipolar cycloaddition reactions of nitrile oxides mediated by pybox/ytterbium triflates, -/magnesium bromide, and -/magnesium perchlorate. It was confirmed that the reactions proceed smoothly to give isoxazoline derivatives in high enantiomeric excesses with Mg 2+ or Yb 3+ complexes and acrylamide dipolarophiles bearing an oxazolidinone or imidazolidinone coordination auxiliary as well as a pybox ligand. In reactions with a dipolarophile bearing 4,4-dimethyloxazolidinone as the coordination auxiliary, an enantiomeric excess (59 % ee) of the corresponding cycloaddition product was achieved by using a slow addition technique to generate nitrile oxides in
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